Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G79/00—Macromolecular compounds obtained by reactions forming a linkage containing atoms other than silicon, sulfur, nitrogen, oxygen, and carbon with or without the latter elements in the main chain of the macromolecule
  • C08G79/14—Macromolecular compounds obtained by reactions forming a linkage containing atoms other than silicon, sulfur, nitrogen, oxygen, and carbon with or without the latter elements in the main chain of the macromolecule a linkage containing two or more elements other than carbon, oxygen, nitrogen, sulfur and silicon
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
  • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
  • G03F7/004—Photosensitive materials
  • G03F7/09—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers
  • G03F7/11—Photosensitive materials characterised by structural details, e.g. supports, auxiliary layers having cover layers or intermediate layers, e.g. subbing layers

Definitions

• Patent Document 1 discloses a lithography material containing a tellurium-containing compound or a tellurium-containing resin as a resist material that reduces film defects and has good storage stability and high sensitivity.
• Lithography materials are increasingly required to satisfy multiple performance requirements. For example, in the semiconductor manufacturing process, heat resistance is also required while solubility in highly safe solvents used is required. In addition, the above properties and film formability are also required at the same time. Therefore, there is a demand for lithography materials that can satisfy these performance requirements at the same time. Therefore, an object of the present invention is to provide a lithography film-forming composition containing a hyperbranched tellurium-containing resin that has high solubility in a solvent, excellent film-forming properties, and high heat resistance.
• lithography film-forming composition containing a multi-branched tellurium-containing resin obtained by an addition reaction between a specific aromatic compound and tellurium tetrachloride can solve the above problems, and thus completed the present invention.
• ⁇ 3> The lithographic film-forming composition according to ⁇ 1> or ⁇ 2>, wherein the aromatic compound is at least one selected from the group consisting of triphenylmethane, tetraphenylmethane, anthracene, perylene, phenanthrene, and naphthalene.
• ⁇ 4> The lithographic film-forming composition according to any one of ⁇ 1> to ⁇ 3>, wherein the aromatic compound includes a compound represented by the following formula (1): (In the formula, R is a hydrogen atom, a methyl group, or a phenyl group.)
• ⁇ 5> The lithographic film-forming composition according to any one of ⁇ 1> to ⁇ 4>, wherein the hyperbranched tellurium-containing resin contains at least one structural unit selected from the group consisting of a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), and a structural unit represented by the following formula (4): (In the formula, R is a hydrogen atom, a methyl group, or a phenyl group.)
• ⁇ 6> The lithographic film-forming composition according to any one of ⁇ 1> to ⁇ 5> above, further comprising a solvent.
• ⁇ 7> The lithographic film-forming composition according to any one of ⁇ 1> to ⁇ 6> above, further comprising at least one selected from the group consisting of an acid generator and an acid crosslinking agent.
• ⁇ 8> The lithography film-forming composition according to any one of ⁇ 1> to ⁇ 7> above, which is a lithography underlayer film-forming composition.
• ⁇ 9> A lithography underlayer film formed from the lithography film-forming composition according to any one of ⁇ 1> to ⁇ 8>.
• ⁇ 10> A method for forming a resist pattern, comprising using the lithographic film-forming composition according to any one of ⁇ 1> to ⁇ 8>.
• the present invention provides a lithography film-forming composition that contains a hyperbranched tellurium-containing resin that has high solubility in solvents, excellent film-forming properties, and high heat resistance.
• the lithographic film-forming composition of the present invention is a lithographic film-forming composition containing a multi-branched tellurium-containing resin obtained by addition reaction of at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds with at least one tellurium compound selected from the group consisting of tellurium tetrachloride and tetraalkoxytellurium, and is preferably a lithographic film-forming composition containing a multi-branched tellurium-containing resin obtained by addition reaction of at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds with tellurium tetrachloride.
• the lithographic film-forming composition of the present invention is a lithographic film-forming composition containing a multi-branched tellurium-containing resin, wherein the multi-branched tellurium-containing resin is a resin obtained by addition reaction of at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds with at least one tellurium compound selected from the group consisting of tellurium tetrachloride and tetraalkoxytellurium, and preferably a lithographic film-forming composition containing a multi-branched tellurium-containing resin, wherein the multi-branched tellurium-containing resin is a resin obtained by addition reaction of at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds with tellurium tetrachloride.
• the multi-branched tellurium-containing resin contained in the lithography film-forming composition of the present invention is a multi-branched tellurium-containing resin obtained by addition reaction of at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds with at least one tellurium compound selected from the group consisting of tellurium tetrachloride and tetraalkoxytellurium, and is preferably a multi-branched tellurium-containing resin obtained by addition reaction of at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds with tellurium tetrachloride.
• Such a hyperbranched tellurium-containing resin has high solubility in solvents, excellent film-forming properties, and high heat resistance, and therefore can be suitably used as a component of a lithography film-forming composition.
• the hyperbranched tellurium-containing resin has a core-shell structure, and while the shell structure mainly contributes to properties such as solubility in solvents, the entire elemental composition including the shell portion contributes to the sensitivity of, for example, EUV exposure, which is an advanced lithography technology, and therefore the resin can have all the necessary properties as a component of a lithography film-forming composition.
• the aromatic compound used as a raw material for the hyperbranched tellurium-containing resin is at least one selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds.
• the aromatic compound preferably contains at least one compound having three or more aromatic rings in one molecule. That is, the aromatic compound preferably contains at least one compound having three or more aromatic rings in one molecule.
• a tellurium-containing resin having a multi-branched structure can be obtained.
• the polyphenyl compound is a compound containing two or more phenyl groups in one molecule, preferably a compound containing three or more phenyl groups in one molecule, more preferably a compound containing three or four phenyl groups in one molecule, and even more preferably a compound containing three phenyl groups in one molecule.
• the use of a compound containing three or more phenyl groups in one molecule is preferred because it allows a tellurium-containing resin with a multi-branched structure to be obtained.
• the polyphenyl compound preferably includes a compound represented by the following formula (1): (In the formula, R is a hydrogen atom, a methyl group, or a phenyl group.)
• R is a hydrogen atom, a methyl group or a phenyl group, and is preferably a hydrogen atom.
• the compound represented by formula (1) is preferably triphenylmethane, tetraphenylmethane, etc., more preferably at least one selected from the group consisting of triphenylmethane and tetraphenylmethane, and even more preferably triphenylmethane.
• the polyphenyl compound is preferably a compound containing three or more phenyl groups in one molecule, but may also include a compound containing two phenyl groups in one molecule.
• Examples of the compound containing two phenyl groups in one molecule include a compound represented by the following formula (5) and a compound represented by the following formula (6). (In the formula, X is an oxygen atom or a sulfur atom.)
• X is an oxygen atom or a sulfur atom, preferably an oxygen atom.
• the condensed polycyclic aromatic hydrocarbon compound is a compound containing a structure in which two or more aromatic rings are condensed in one molecule, preferably a compound containing a structure in which three or more aromatic rings are condensed in one molecule, and more preferably a compound containing a structure in which three or four aromatic rings are condensed in one molecule.
• the use of a compound containing a structure in which two or more aromatic rings are condensed is preferred because a tellurium-containing resin having a multi-branched structure can be obtained, and the use of a compound containing a structure in which three or more aromatic rings are condensed is even more preferred because a tellurium-containing resin having a multi-branched structure can also be obtained.
• Preferred examples of the condensed polycyclic aromatic hydrocarbon compound include anthracene (a compound having a structure in which three aromatic rings are condensed), perylene (a compound having a structure in which five aromatic rings are condensed), phenanthrene (a compound having a structure in which three aromatic rings are condensed), and naphthalene (a compound having a structure in which two aromatic rings are condensed), and more preferred examples are at least one selected from the group consisting of anthracene, perylene, phenanthrene, and naphthalene.
• the aromatic compound is preferably at least one selected from the group consisting of triphenylmethane, tetraphenylmethane, anthracene, perylene, phenanthrene, and naphthalene, more preferably at least one selected from the group consisting of triphenylmethane and tetraphenylmethane, and even more preferably triphenylmethane.
• the tellurium compound used as a raw material for the hyperbranched tellurium-containing resin is at least one tellurium compound selected from the group consisting of tellurium tetrachloride and tetraalkoxytellurium, and is preferably tellurium tetrachloride.
• tetraalkoxytellurium include tetramethoxytellurium, tetraethoxytellurium, tetraisopropoxytellurium, and the like. From the viewpoint of availability, at least one selected from the group consisting of tetraethoxytellurium and tetraisopropoxytellurium is preferred, and tetraethoxytellurium is more preferred.
• the hyperbranched tellurium-containing resin contained in the lithographic film-forming composition of the present invention preferably contains at least one structural unit selected from the group consisting of a structural unit represented by the following formula (2), a structural unit represented by the following formula (3), and a structural unit represented by the following formula (4).
• the hyperbranched tellurium-containing resin contains such a structural unit, it has higher solubility in solvents, better film-forming properties, and higher heat resistance, and is more suitably used as a component of the lithographic film-forming composition.
• R is a hydrogen atom, a methyl group, or a phenyl group.
• R is a hydrogen atom, a methyl group or a phenyl group, and is preferably a hydrogen atom.
• R is a hydrogen atom, a methyl group or a phenyl group, and is preferably a hydrogen atom.
• R is a hydrogen atom, a methyl group or a phenyl group, and is preferably a hydrogen atom.
• the number average molecular weight of the hyperbranched tellurium-containing resin contained in the lithography film-forming composition of the present invention is preferably 1000 to 10000, more preferably 1500 to 8000, even more preferably 1500 to 5000, and still more preferably 2000 to 5000. By having the number average molecular weight in the above range, the composition has high solubility in solvents, excellent film-forming properties, and high heat resistance.
• the number average molecular weight of the hyperbranched tellurium-containing resin is more preferably 2,000 to 10,000, even more preferably 3,000 to 9,000, and still more preferably 5,000 to 9,000, particularly from the viewpoint of heat resistance.
• the molecular weight distribution (Mw/Mn) of the hyperbranched tellurium-containing resin is preferably 1.5 to 10.0, more preferably 1.5 to 7.0, even more preferably 1.5 to 4.0, and still more preferably 1.5 to 2.5.
• the resin has high solubility in a solvent, excellent film-forming properties, and high heat resistance.
• the multi-branched tellurium-containing resin also has a high absorption capacity for soft X-rays and X-rays with wavelengths of 3 to 20 nm, and therefore a high absorption capacity for EUV light within the wavelength range. Therefore, the multi-branched tellurium-containing resin can be suitably used, for example, in lithography film-forming compositions that use EUV as exposure light for cutting-edge microfabrication.
• the multi-branched tellurium-containing resin contained in the lithography film-forming composition of the present invention is not limited in its manufacturing method, as long as it is obtained by addition reaction of at least one aromatic compound selected from the group consisting of polyphenyl compounds and condensed polycyclic aromatic hydrocarbon compounds with at least one tellurium compound selected from the group consisting of tellurium tetrachloride and tetraalkoxytellurium.
• the molar ratio of the aromatic rings of the aromatic compound to the tellurium atoms of tellurium tetrachloride is preferably 50/50 to 95/5, more preferably 60/40 to 95/5, even more preferably 70/30 to 95/5, and from the viewpoint of obtaining a high molecular weight compound, still more preferably 80/20 to 92/8.
• the molar ratio of phenyl groups in the polyphenyl compound to tellurium atoms in tellurium tetrachloride is preferably 50/50 to 95/5, more preferably 60/40 to 95/5, even more preferably 70/30 to 95/5, and from the viewpoint of obtaining a high molecular weight compound, still more preferably 80/20 to 92/8.
• the molar ratio of the compound represented by formula (1) to tellurium tetrachloride is preferably 30/70 to 80/20, more preferably 40/60 to 80/20, even more preferably 50/50 to 80/20, and from the viewpoint of obtaining a high molecular weight compound, still more preferably 60/40 to 80/20.
• the molar ratio of triphenylmethane to tellurium tetrachloride is preferably 30/70 to 80/20, more preferably 40/60 to 80/20, even more preferably 50/50 to 80/20, and from the viewpoint of obtaining a high molecular weight substance, still more preferably 60/40 to 80/20.
• the reaction temperature is preferably 0 to 100°C, more preferably 20 to 80°C, and further preferably 30 to 70°C.
• the reaction time may be appropriately adjusted depending on the reaction temperature, the amount of catalyst, the reactivity of the raw materials, the target molecular weight, and the like, but is preferably 1 to 72 hours, more preferably 5 to 60 hours, and even more preferably 12 to 50 hours.
• the reaction may be carried out in the presence of a solvent.
• a solvent are those in which the resulting multi-branched tellurium-containing resin dissolves, more preferably halogenated organic solvents, even more preferably halogenated hydrocarbons, and even more preferably chloroform.
• the obtained multi-branched tellurium-containing resin is preferably purified by a normal post-treatment. Specifically, it is preferable to remove raw materials and by-products by pouring the reaction mixture into an organic solvent in which the multi-branched tellurium-containing resin is not dissolved, and recovering the desired multi-branched tellurium-containing resin as a precipitate.
• the multi-branched tellurium-containing resin it is also preferable to dissolve the multi-branched tellurium-containing resin in an organic solvent in which the multi-branched tellurium-containing resin is dissolved, and wash with water or the like to remove catalysts and the like.
• the hyperbranched tellurium-containing resin it is preferable to obtain the hyperbranched tellurium-containing resin as a solid by concentrating and drying.
• the hyperbranched tellurium-containing resin obtained in the above manner has high solubility in solvents, excellent film-forming properties, and high heat resistance.
• the lithographic film-forming composition of the present invention preferably further contains a solvent in addition to the hyperbranched tellurium-containing resin.
• the lithographic film-forming composition of the present invention preferably further contains at least one selected from the group consisting of an acid generator and an acid crosslinking agent, and more preferably contains both an acid generator and an acid crosslinking agent.
• the lithographic film-forming composition of the present invention may further contain, as other optional components, an acid or base compound, an acid diffusion controller, an organic polymer compound, a surfactant, a colorant, a curing catalyst, and the like.
• the content of the hyperbranched tellurium-containing resin in the lithography film-forming composition of the present invention is preferably 0.1 to 70% by mass, more preferably 0.5 to 50% by mass, and even more preferably 3.0 to 40% by mass, from the viewpoints of coatability and quality stability.
• the lithographic film-forming composition of the present invention preferably further contains a solvent.
• the solvent is not particularly limited as long as it dissolves the multi-branched tellurium-containing resin and the components, such as the acid generator, which are optionally contained, but the following solvents are preferred.
• the solvent examples include ethylene glycol monoalkyl ether acetates such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-propyl ether acetate, and ethylene glycol mono-n-butyl ether acetate; ethylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether and ethylene glycol monoethyl ether; propylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate (PGMEA), propylene glycol mono-n-propyl ether acetate, and propylene glycol mono-n-butyl ether acetate; propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether (PGME) and propylene glycol monoethyl ether; lactate esters such as methyl lactate
• the solvent contained in the lithographic film-forming composition of the present invention is preferably a safe solvent, more preferably at least one selected from PGMEA, PGME, CHN, CPN, 2-heptanone, anisole, butyl acetate, ethyl propionate, ethyl lactate, THF, and DMF, and even more preferably at least one selected from PGMEA, PGME, CHN, THF, and DMF.
• the content of the solvent in the lithographic film-forming composition of the present invention is preferably 100 to 10,000 parts by mass, more preferably 200 to 8,000 parts by mass, and even more preferably 200 to 5,000 parts by mass, relative to 100 parts by mass of the total solid components (components excluding the solvent) of the lithographic film-forming composition.
• the acid generator is preferably an acid generator that generates an acid directly or indirectly upon irradiation with any radiation selected from visible light, ultraviolet light, an excimer laser, an electron beam, extreme ultraviolet light (EUV), X-rays, and an ion beam.
• the content of the acid generator is preferably 0.001 to 49 mass %, more preferably 1 to 40 mass %, even more preferably 3 to 30 mass %, still more preferably 5 to 25 mass %, and even more preferably 10 to 25 mass %, based on the total mass of the solid components (components excluding the solvent).
• the method of generating the acid is not limited. If an excimer laser is used as radiation instead of ultraviolet rays such as g-rays and i-rays, finer processing is possible, and if an electron beam, extreme ultraviolet rays, X-rays, or ion beams are used as high-energy rays, further finer processing is possible.
• the acid generator is not particularly limited, and examples thereof include the compounds disclosed in WO 2017/033943.
• the acid generator is preferably an acid generator having an aromatic ring, more preferably an acid generator having a sulfonate ion having an aryl group, and even more preferably at least one selected from the group consisting of diphenyltrimethylphenylsulfonium p-toluenesulfonate, triphenylsulfonium p-toluenesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoromethanesulfonate, ditertiarybutyldiphenyliodonium nonafluorobutanesulfonate, and pyridinium p-toluenesulfonate.
• line edge roughness can be reduced.
• the lithography film-forming composition of the present invention preferably further contains a diazonaphthoquinone photoactive compound as an acid generator.
• the diazonaphthoquinone photoactive compound is a diazonaphthoquinone substance including polymeric and non-polymeric diazonaphthoquinone photoactive compounds, and is not particularly limited as long as it is generally used as a photosensitive component in a positive resist composition, and one or more types can be arbitrarily selected and used.
• a non-polymeric diazonaphthoquinone photoactive compound is preferable, and a low molecular weight compound is more preferable, and the molecular weight is preferably 1500 or less, more preferably 1200 or less, and even more preferably 1000 or less.
• a preferred specific example of such a non-polymeric diazonaphthoquinone photoactive compound includes the non-polymeric diazonaphthoquinone photoactive compound disclosed in International Publication No. 2016/158881.
• the acid generator can be used alone or in combination of two or more types.
• the lithographic film-forming composition of the present invention preferably contains an acid crosslinker in order to increase the strength of the pattern, whether it is used as a negative resist material or a positive resist material.
• the acid crosslinking agent is a compound capable of intramolecularly or intermolecularly crosslinking a resin in the presence of an acid generated from an acid generator.
• Such an acid crosslinking agent is not particularly limited, but may be a compound having one or more crosslinkable groups capable of crosslinking a resin.
• crosslinkable group examples include, but are not limited to, (i) hydroxyalkyl groups such as hydroxy (alkyl groups having 1 to 6 carbon atoms), alkoxy (alkyl groups having 1 to 6 carbon atoms), and acetoxy (alkyl groups having 1 to 6 carbon atoms), or groups derived therefrom; (ii) carbonyl groups such as formyl and carboxy (alkyl groups having 1 to 6 carbon atoms), or groups derived therefrom; (iii) dimethylaminomethyl groups, diethylaminomethyl groups, dimethylolaminomethyl groups, diethylolaminomethyl groups, and the like.
• crosslinkable group examples include nitrogen-containing groups such as arylaminomethyl and morpholinomethyl groups; (iv) glycidyl group-containing groups such as glycidyl ether, glycidyl ester and glycidylamino groups; (v) groups derived from aromatic groups such as allyloxy (alkyl groups having 1 to 6 carbon atoms) and aralkyloxy (alkyl groups having 1 to 6 carbon atoms) having 1 to 6 carbon atoms, such as benzyloxymethyl and benzoyloxymethyl groups; and (vi) polymerizable multiple bond-containing groups such as vinyl and isopropenyl groups.
• the crosslinkable group examples include hydroxyalkyl groups and alkoxyalkyl groups, and more preferably alkoxymethyl groups.
• the acid crosslinking agent examples include, but are not limited to, (i) methylol group-containing compounds such as methylol group-containing melamine compounds, methylol group-containing benzoguanamine compounds, methylol group-containing urea compounds, methylol group-containing glycoluril compounds, and methylol group-containing phenol compounds; (ii) alkoxyalkyl group-containing compounds such as alkoxyalkyl group-containing melamine compounds, alkoxyalkyl group-containing benzoguanamine compounds, alkoxyalkyl group-containing urea compounds, alkoxyalkyl group-containing glycoluril compounds, and alkoxyalkyl group-containing phenol compounds; (iii) carboxymethyl group-containing compounds such as carboxymethyl group-containing melamine compounds, carboxymethyl group-containing benzoguanamine compounds, carboxymethyl group-containing urea compounds, carboxymethyl group-containing glycoluril compounds, and carboxymethyl group-containing phenol compounds; and (
• the acid crosslinking agent a compound having a phenolic hydroxyl group, and a compound and resin in which the crosslinkable group is introduced into the acidic functional group in an alkali-soluble resin to impart crosslinking properties can be used.
• the introduction rate of the crosslinkable group is not particularly limited, and is preferably 5 to 100 mol%, more preferably 10 to 60 mol%, and even more preferably 15 to 40 mol% based on the total acidic functional groups in the compound having a phenolic hydroxyl group and the alkali-soluble resin.
• the introduction rate is within the above range, the crosslinking reaction occurs sufficiently, and a decrease in the residual film rate and a swelling phenomenon or meandering of the pattern can be avoided, which is preferable.
• the acid crosslinker is preferably at least one selected from an alkoxyalkylated urea compound or a resin thereof, or an alkoxyalkylated glycoluril compound or a resin thereof (acid crosslinker (1)), a phenol derivative having 1 to 6 benzene rings in the molecule and having two or more hydroxyalkyl groups or alkoxyalkyl groups throughout the molecule, with the hydroxyalkyl groups or alkoxyalkyl groups being bonded to any of the benzene rings (acid crosslinker (2)), and a compound having at least one ⁇ -hydroxyisopropyl group (acid crosslinker (3)).
• acid crosslinker (1) an alkoxyalkylated urea compound or a resin thereof, or an alkoxyalkylated glycoluril compound or a resin thereof
• acid crosslinker (1) a phenol derivative having 1 to 6 benzene rings in the molecule and having two or more hydroxyalkyl groups or alkoxyalkyl groups throughout the molecule
• the content of the acid crosslinker is preferably 0.5 to 49 mass %, more preferably 0.5 to 40 mass %, even more preferably 1 to 30 mass %, and even more preferably 2 to 20 mass %, based on the total mass of the solid components (components excluding the solvent).
• the content of the acid crosslinker is 0.5 mass % or more, the effect of suppressing the solubility of the resist film in an alkaline developer is improved, and it is preferable that the residual film rate is reduced and the swelling or meandering of the pattern is suppressed.
• the content is 49 mass % or less, it is preferable that the decrease in heat resistance as a resist is suppressed.
• the contents of the acid crosslinking agent (1), the acid crosslinking agent (2), and the acid crosslinking agent (3) in the acid crosslinking agent are not particularly limited and can be selected depending on factors such as the type of substrate used when forming a resist pattern.
• the lithographic film-forming composition of the present invention may further contain an acid diffusion control agent, and preferably further contains an acid diffusion control agent.
• the acid diffusion control agent optionally contained in the lithographic film-forming composition of the present invention has the effect of controlling the diffusion of the acid generated from the acid generator by radiation exposure in the resist film, thereby preventing undesirable chemical reactions in unexposed areas. Therefore, the storage stability of the lithographic film-forming composition can be improved, and the resolution can be improved. In addition, the change in line width of the resist pattern caused by the variation in the exposure time before radiation exposure and the exposure time after radiation exposure can be suppressed, resulting in extremely excellent process stability.
• the acid diffusion control agent may be a radiolytic basic compound such as a nitrogen atom-containing basic compound, a basic sulfonium compound, or a basic iodonium compound.
• the acid diffusion control agent may be a compound disclosed in WO 2017/033943.
• the acid diffusion control agent may be used alone or in combination of two or more types.
• the content of the acid diffusion control agent is preferably 0.001 to 49% by mass based on the total mass of the solid components (components excluding the solvent), and from the viewpoint of preventing a decrease in sensitivity, developability of unexposed areas, etc., it is more preferably 0.01 to 10% by mass, even more preferably 0.01 to 5% by mass, and even more preferably 0.01 to 3% by mass.
• the shape of the upper layer of the resist pattern does not deteriorate when the waiting time from electron beam irradiation until heating after radiation irradiation is long.
• the lithography film-forming composition of the present invention is a composition capable of forming a resist top layer film, a resist underlayer film, etc., and is preferably a lithography underlayer film-forming composition.
• the lithography film-forming composition of the present invention has a multi-branched tellurium-containing resin that is highly soluble in a solvent, has excellent film-forming properties, and has high heat resistance.
• the lithography film-forming composition is preferably used as a lithography underlayer film-forming composition, that is, the lithography underlayer film-forming composition is a lithography film-forming composition containing the hyperbranched tellurium-containing resin.
• the lithography underlayer film forming composition can form an underlayer film for lithography such as a resist underlayer film, and has high heat resistance and excellent solubility in a solvent. Therefore, the rectangular shape of the pattern is excellent. In addition, the film forming property is excellent.
• the composition for forming a lithography underlayer film is capable of forming a lithography underlayer film having excellent flatness.
• the lithography underlayer film forming composition can be suitably used, for example, in a multilayer resist method in which a resist underlayer film is further provided between an upper layer resist (photoresist, etc.) and a hard mask or an organic underlayer film.
• a resist underlayer film is formed on an organic underlayer film or a hard mask on a substrate by a coating method or the like, and an upper layer resist (for example, a photoresist, an electron beam resist, an EUV resist) is formed on the resist underlayer film.
• a resist pattern is formed by exposure and development, and the resist underlayer film is dry-etched using the resist pattern to transfer the pattern, and the organic underlayer film is etched to transfer the pattern, and the substrate is processed using the organic underlayer film. That is, the lithography underlayer film (resist underlayer film) formed using the lithography film-forming composition of the present invention is unlikely to cause intermixing with the upper resist layer, has heat resistance, and can obtain a good rectangular pattern.
• the lithography film-forming composition of the present invention can also be used in an embodiment in which a plurality of resist underlayer films are laminated.
• the position (which layer is laminated) of the resist underlayer film formed using the lithography film-forming composition of the present invention is not particularly limited, and it may be directly under the upper resist layer, may be the layer located closest to the substrate, or may be sandwiched between the resist underlayer films.
• the resist film tends to be thin in order to prevent the pattern from collapsing.
• the dry etching for transferring the pattern to the film existing in the lower layer by thinning the resist must have a higher etching rate than the film in the upper layer in order to transfer the pattern.
• the substrate can be covered with the resist underlayer film of the present invention via an organic underlayer film, and the resist film (organic resist film) can be further covered on the organic underlayer film.
• the organic underlayer film underneath can be dry etched with an oxygen-based gas to transfer the pattern to the organic underlayer film, and then the organic underlayer film to which the pattern has been transferred can be used to process the substrate using a halogen-containing gas.
• the resist underlayer film made of the lithography film-forming composition of the present invention has high heat resistance, so it can be used under high-temperature baking conditions.Furthermore, because it has a relatively low molecular weight and low viscosity, it is easy to fill evenly into every corner of a substrate with a step (especially a fine space or hole pattern, etc.), and as a result, the planarization property and filling property tend to be relatively advantageously improved.
• the hyperbranched tellurium-containing resin contained in the lithography film-forming composition of the present invention has high solubility in solvents, excellent film-forming properties, and high heat resistance, and therefore it is preferable to form a lithography underlayer film using the lithography film-forming composition, which is a lithography underlayer film-forming composition. That is, the lithography underlayer film of the present invention is a lithography underlayer film formed from the lithography film-forming composition.
• the lithography underlayer film of the present invention can be suitably used as an underlayer (resist underlayer film) of a photoresist (upper layer) used in a multilayer resist method.
• the lithography underlayer film of the present invention is not particularly limited in its formation method as long as it is formed from the lithography film-forming composition of the present invention, and known methods can be applied.
• the lithography underlayer film can be formed by applying the lithography film-forming composition onto a substrate by known coating or printing methods such as spin coating or screen printing, and then removing the organic solvent.
• the lithography underlayer film of the present invention can be suitably used as an underlayer film of an EUV resist.
• the film formed from the lithography film-forming composition has excellent EUV absorption ability, and is therefore capable of exerting a sensitizing effect on the upper layer resist composition, contributing to improved sensitivity.
• the process in which the lithography underlayer film of the present invention is used as an underlayer film of an EUV resist can also be carried out by a known method.
• the lithography film-forming composition of the present invention is excellent as a material for forming a lithography underlayer film, so it is preferable to form a resist pattern by a resist pattern forming method having a step of forming a lithography underlayer film on a substrate using the lithography film-forming composition. That is, the method of forming a resist pattern of the present invention is a method of forming a resist pattern using the lithographic film-forming composition of the present invention.
• a suitable pattern forming method of the present invention is a method for forming a resist pattern, comprising the steps of forming an underlayer film precursor on a substrate using the lithography film-forming composition, and heating the underlayer film precursor to 300° C. or higher to form an underlayer film, forming at least one photoresist layer on the underlayer film, and irradiating the photoresist layer with radiation and performing development.
• the step of forming an underlayer film is a step of forming an underlayer film precursor on a substrate using the lithography film-forming composition, and heating the underlayer film precursor to 300° C. or higher to form an underlayer film.
• the substrate used in this step may be a semiconductor substrate.
• the semiconductor substrate may generally be a silicon substrate (silicon wafer), but is not particularly limited thereto.
• the semiconductor substrate may be made of a material different from that of the layer to be processed, such as Si, amorphous silicon ( ⁇ -Si), p-Si, SiO 2 , SiN, SiON, W, TiN, or Al.
• a metal film, a metal carbide film, a metal oxide film, a metal nitride film, a metal oxide carbide film, or a metal oxide nitride film may be formed on the semiconductor substrate as a layer to be processed (a portion to be processed).
• Examples of such a metal-containing layer to be processed include Si, SiO 2 , SiN, SiON, SiOC, p-Si, ⁇ -Si, TiN, WSi, BPSG, SOG, Cr, CrO, CrON, MoSi, W, W-Si, Al, Cu, Al-Si, and various low dielectric films and their etching stopper films, and can be formed to a thickness of usually 50 to 10,000 nm, particularly 100 to 5,000 nm.
• This step is a step of forming an underlayer film on a substrate using the lithography film-forming composition, but before forming an underlayer film using the lithography film-forming composition, an organic underlayer film or an organic hard mask can be formed on the substrate.
• the organic underlayer film can be formed from a coating-type organic underlayer film material using a spin coating method or the like, and the organic hard mask can be formed from an organic hard mask material mainly composed of carbon using a CVD method.
• the types of such organic underlayer film and organic hard mask are not particularly limited, but when the upper resist film is patterned by exposure, it is preferable that the organic underlayer film and organic hard mask have a sufficient anti-reflective film function.
• a hard mask "mainly composed of carbon” means a hard mask in which 50 mass % or more of the solid content is composed of a carbon-based material such as amorphous hydrogenated carbon, also called amorphous carbon and indicated as a-C:H.
• the a-C:H film can be deposited by various techniques, but plasma enhanced chemical vapor deposition (PECVD) is widely used due to its cost-effectiveness and film quality controllability. Examples of the hard mask can be found in JP2013-526783A.
• this process is a process of forming an organic underlayer film on a substrate, forming an underlayer film precursor on the organic underlayer film using the lithography film-forming composition, and heating the underlayer film precursor to 300°C or higher to form an underlayer film.
• the process includes forming an organic hard mask on a substrate, forming an underlayer film precursor on the organic hard mask using the lithography film-forming composition, and heating the underlayer film precursor to 300° C. or higher to form an underlayer film.
• the method for forming the underlayer film precursor using the lithography film-forming composition is preferably to form it on a substrate or on a workpiece provided with an organic underlayer film or the like by spin coating or the like.
• the lithography film-forming composition is first applied onto the substrate or the workpiece.
• the content of the multi-branched tellurium-containing resin contained in the lithography film-forming composition may be appropriately adjusted in consideration of the rotation speed and rotation time of spin coating, the viscosity of the composition, and the evaporation rate of the solvent.
• the content of the multi-branched tellurium-containing resin contained in the lithography film-forming composition is preferably 0.001 to 10 g per 100 mL of the solvent contained in the lithography film-forming composition.
• the organic solvent is then removed by volatilization to form an underlayer film precursor.
• the thickness of the underlayer film precursor is preferably adjusted to 1 to 200 nm by adjusting the content of the multi-branched tellurium-containing resin, the rotation speed of spin coating, the rotation time, etc.
• the bake temperature is preferably 300°C or higher, more preferably 300 to 450°C, and even more preferably 300 to 400°C.
• the bake time is not particularly limited, but is preferably 10 to 300 seconds.
• the underlayer film is formed on the substrate.
• the thickness of the underlayer film can be appropriately selected depending on the required performance, and is not particularly limited, but is preferably 30 to 20,000 nm, and more preferably 50 to 15,000 nm.
• a step of forming a photoresist layer is performed.
• the step of forming a photoresist layer is a step of forming at least one photoresist layer on the underlayer film.
• This process is a process for forming a photoresist layer on an underlayer film.
• photoresist materials used for the photoresist layer include those that form a photoresist film, expose it, and then dissolve the exposed areas using an alkaline developer to form a positive pattern, and those that dissolve the unexposed areas using a developer made of an organic solvent to form a negative pattern.
• a wet process such as spin coating or screen printing is preferably used.
• pre-baking is usually performed, and this pre-baking is preferably performed under conditions of a baking temperature of 80 to 180° C. and a baking time of 10 to 300 seconds.
• the thickness of the photoresist layer is not particularly limited, but is generally preferably 30 to 500 nm, more preferably 50 to 400 nm.
• the developing step is a step of irradiating the photoresist layer with radiation and developing it. In this step, exposure and development are carried out as described above, thereby obtaining a resist pattern.
• the radiation (exposure light) to be irradiated onto the photoresist layer may be appropriately selected depending on the photoresist material used.
• high-energy rays having a wavelength of 300 nm or less specifically, excimer lasers having wavelengths of 248 nm, 193 nm, and 157 nm, soft X-rays having wavelengths of 3 to 20 nm, electron beams, X-rays, and the like can be used.
• any one of the following methods can be suitably used: lithography using light having a wavelength of 300 nm or less or EUV light; electron beam direct writing method; and directed self-organization method.
• the developing method may be appropriately selected depending on the photoresist material that is the raw material of the photoresist layer used.
• a positive pattern it is preferable to form a positive pattern by dissolving the exposed areas using an alkaline developer, and when a negative pattern is to be formed, it is preferable to form a negative pattern by dissolving the unexposed areas using a developer consisting of an organic solvent. In this manner, a resist pattern can be obtained.
• a process using a lithography underlayer film obtained using the lithography film-forming composition is particularly suitable for use.
• the lithography underlayer film obtained using the lithography film-forming composition of the present invention has excellent exposure light absorption ability, and is therefore capable of exerting a sensitizing effect on the upper layer resist composition.
• EUV light can also be suitably used as the exposure light, which is believed to be because tellurium atoms contained in the lithography underlayer film contribute to the absorption of EUV light.
• the pattern formation method of the present invention preferably includes the steps of: transferring a pattern to an underlayer film by etching using the resist pattern formed on the upper layer as described above as a mask; transferring a pattern to the organic underlayer film by etching using the resist underlayer film to which the pattern has been transferred as a mask; and further transferring a pattern to the substrate (workpiece) by etching using the organic underlayer film to which the pattern has been transferred as a mask.
• the pattern formation method of the present invention includes the steps of transferring a pattern to the underlayer film by etching using the resist pattern formed on the upper layer as described above as a mask, transferring a pattern to the organic hard mask by etching using the underlayer film to which the pattern has been transferred as a mask, and further transferring a pattern to the substrate (workpiece) by etching using the organic hard mask to which the pattern has been transferred as a mask.
• FT-IR Fourier transform infrared spectroscopy
• JASCO JASCO Corporation
• 1 H-NMR spectrum was measured using FTECS-400K (manufactured by JEOL Ltd.) under conditions of a frequency of 400 MHz, DMSO-d 6 as a solvent, and Me 4 Si (TMS) as an internal standard.
• the number average molecular weight (Mn) and molecular weight distribution (Mw/Mn) of the resin were measured by size exclusion chromatography (SEC) under the following conditions. Standard polystyrene (narrow molecular weight distribution) was used for calibration.
• Thermal stability (heat resistance)> The thermal stability of the multi-branched tellurium-containing resin was measured by heating at a heating rate of 10° C./min under nitrogen using a thermogravimetric analyzer (TGA) TGA-50/50H (manufactured by Shimadzu Corporation). When the weight loss at 90° C. is 3% or less, the thermal stability is excellent, and when the weight loss at 90° C. is 0% (temperature at which thermal decomposition starts higher than 90° C.), the thermal stability is even more excellent.
• TGA thermogravimetric analyzer
• the multi-branched tellurium-containing resins obtained in Production Examples 1 to 5 have excellent thermal stability as described below, when used as a raw material for a lithography film-forming composition, they can withstand high temperatures of about 100° C. during pre-baking and post-baking (PEB). The thermal stability was evaluated as "good” when the thermal decomposition start temperature exceeded 100° C.
• solubility of the hyperbranched tellurium-containing resin was confirmed by dissolving it in the following solvents at room temperature (25° C.).
• the solvents tested were PGMEA, PGME, MEK, DMSO (dimethyl sulfoxide), DMF (N,N-dimethylformamide), THF (tetrahydrofuran), and chloroform.
• the solubility was evaluated as good when 10 g or more of the resin was dissolved in 100 mL of the solvent. In Table 1, when the solubility was evaluated as good for all of the above solvents, the solubility was indicated as "good.”
• lithography film-forming composition obtained in the examples (a composition containing 10 mg of a hyperbranched tellurium-containing resin (poly(Te-TMP)) and each of the solvents (100 mL) shown in the above solubility evaluation) was applied by spin coating onto a silicon wafer treated with hexamethyldisilazane (HMDS), and dried at 110° C. for 1 minute to form a resist film having a thickness of 10 nm.
• HMDS hexamethyldisilazane
• the thermal decomposition onset temperature was 270°C
• the weight residue at 450°C was 80% or more.
• solubility 10 g of the hyperbranched tellurium-containing resin (poly(Te-TMP)) obtained in Production Examples 1 and 2 was dissolved in each of the various solvents (100 mL) shown in the above-mentioned evaluation of solubility to obtain a lithography film-forming composition, and the solubility was evaluated by the above-mentioned method.
• An example using the hyperbranched tellurium-containing resin (poly(Te-TMP)) of Production Example 1 is taken as Example 1
• an example using the hyperbranched tellurium-containing resin (poly(Te-TMP)) of Production Example 2 is taken as Example 2.
• the solubility and film-forming properties were good regardless of which solvent was used.
• the hyperbranched tellurium-containing resin contained in the lithography film-forming composition of the present invention has high solubility in solvents, excellent film-forming properties, and high heat resistance. Therefore, the lithography film-forming composition of the present invention is an excellent material for forming lithography films, and is particularly excellent as a material for forming lithography underlayer films.
• a four-neck flask with an internal volume of 0.5 L equipped with a Dimroth condenser, a thermometer, and a stirring blade was prepared.
• 100 g (0.51 mol) of the dimethylnaphthalene formaldehyde resin and 0.05 g of paratoluenesulfonic acid were charged under a nitrogen gas flow, and the temperature was raised to 190° C. and heated for 2 hours, and then stirred. Then, 52.0 g (0.36 mol) of 1-naphthol was added, and the temperature was raised to 220° C. and reacted for 2 hours.
• a modified resin (CR-1) as a black-brown solid.
• the obtained resin (CR-1) had Mn: 885, Mw: 2220, and Mw/Mn: 4.17.
• the Mn, Mw and Mw/Mn of the resin (CR-1) were determined in terms of polystyrene by gel permeation chromatography (GPC) analysis under the following measurement conditions.
• GPC gel permeation chromatography Apparatus: Shodex GPC-101 (manufactured by Showa Denko K.K.) Column: KF-80M x 3 Eluent: THF 1 mL/min Temperature: 40°C
• Examples A1 to A9 and Comparative Example A1 (Preparation of Lithographic Film-Forming Composition) Using the poly(Te-TMP) obtained in Preparation Examples 1 to 5 or CR-1 obtained in Comparative Preparation Example 1, each component was mixed until homogeneous according to the composition shown in Table 2 to prepare a lithography film-forming composition having the composition shown in Table 2.
• a composition for etching rate evaluation was obtained in the same manner as in Example A1, except that a novolak resin (PSM4357 (model number), manufactured by Gun-ei Chemical Industry Co., Ltd.) was used instead of the poly(Te-TMP) obtained in Production Example 1.
• TPS-109 Triphenylsulfonium trifluoromethanesulfonate, TPS-109 (trade name), manufactured by Midori Chemical Industry Co., Ltd.
• DTDPI Di-tertiary-butyldiphenyliodonium nonafluorobutanesulfonate (DTDPI), manufactured by Midori Chemical Industry Co., Ltd.
• PPTS Pyridinium paratoluenesulfonate, manufactured by Kanto Chemical Industry Co., Ltd.
• THF Tetrahydrofuran
• PGME Propylene glycol monomethyl ether
• the shape of the resulting resist pattern with L/S (1:1) and 50 nm spacing was observed using an electron microscope (S-4800, product name, manufactured by Hitachi, Ltd.).
• the resist pattern shape after development was evaluated according to the following criteria. The evaluation results are shown in Table 2.
• C Equivalent to or inferior to Comparative Example A1. In Comparative Example A1, the resist pattern shape after development showed pattern collapse and poor rectangularity.
• the etching resistance of each resist film was evaluated according to the following evaluation criteria, based on the etching rate of the resist film obtained from the evaluation standard composition using novolac resin. The evaluation results are shown in Table 2.
• the acid generator, acid crosslinker, and organic solvent used were as follows: In Table 3, the numbers in parentheses indicate the blend amounts (parts by mass).
• DTDPI di-tertiary butyl diphenyl iodonium nonafluorobutanesulfonate (DTDPI), manufactured by Midori Chemical Industry Co., Ltd.
• TPS-109 triphenylsulfonium trifluoromethanesulfonate, TPS-109 (trade name), manufactured by Midori Chemical Industry Co., Ltd.
• PPTS pyridinium paratoluenesulfonate, manufactured by Kanto Chemical Industry Co., Ltd.
• resist underlayer film (lithography underlayer film)
• the lithography film-forming composition shown in Table 3 was spin-coated onto a silicon wafer treated with hexamethyldisilazane (HMDS), and then baked at 240° C. for 60 seconds and then at 400° C. for 120 seconds to form a resist underlayer film (lithography underlayer film) having a thickness of 70 nm.
• HMDS hexamethyldisilazane
• a photoresist film having a thickness of 140 nm was formed by applying an ArF resist solution onto the resist underlayer film formed in (1) above and baking for 60 seconds at 130° C.
• the ArF resist solution was prepared by mixing 5 parts by mass of the resin (AC-1) obtained in Synthesis Example 1 above, 1 part by mass of triphenylsulfonium nonafluoromethanesulfonate, 2 parts by mass of tributylamine, and 92 parts by mass of PGMEA.
• the photoresist film was then exposed to light using an electron beam lithography system "ELS-7500" (product name, Elionix Co., Ltd., 50 keV). It was then baked (PEB) at 115°C for 90 seconds, and developed with a 2.38% by mass aqueous solution of tetramethylammonium hydroxide (TMAH) for 60 seconds to obtain a positive resist pattern.
• ELS-7500 electron beam lithography system
• TMAH tetramethylammonium hydroxide
• Example B1 a photoresist film was directly formed on a silicon wafer in the same manner as in Example B1, except that no resist underlayer film was formed, to obtain a positive resist pattern, and the obtained resist pattern was evaluated in the same manner as described above. This was designated Comparative Example B1. The results are shown in Table 3.
• the resist film formed using the lithographic film-forming composition of the examples containing a hyperbranched tellurium-containing resin can obtain a resist pattern with excellent pattern shape and also has excellent etching resistance. Furthermore, it can be seen that a resist underlayer film (lithography underlayer film) formed using the lithography film-forming composition of the examples containing a hyperbranched tellurium-containing resin can form a resist pattern having excellent resolution.
• the lithography film-forming composition of the present invention contains a hyperbranched tellurium-containing resin that has high solubility in solvents, excellent film-forming properties, and high heat resistance, and is therefore useful as a lithography film-forming material, and is particularly useful as a composition for forming a resist film and a resist underlayer film (lithography underlayer film).

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